Catch Overflow!

"""
https://codeforces.com/problemset/problem/1175/B
"""
import re

def st(s):
  flag = True
  while(flag):
    if(len(s)>2 and s[-2].isdigit() and s[-1].isdigit()):
      a,b = int(s[-2]), int(s[-1])
      s = s[:-2]
      s.append(str(a*10+b))
    elif(len(s)>=3 and s[-3] == '(' and s[-2].isdigit() and s[-1]== ')'):
      a = s[-2]
      s = s[:-3]
      s.append(a)
    elif(len(s)>=3 and s[-3].isdigit() and s[-2]=='+' and s[-1].isdigit()):
      a,b = int(s[-1]),int(s[-3])
      s = s[:-3]
      s.append(str(a+b))
    elif(len(s)>=3 and s[-3].isdigit() and s[-2]=='*' and s[-1].isdigit()):
      a,b = int(s[-1]),int(s[-3])
      s = s[:-3]
      s.append(str(a*b))
    else:
      flag = False

  return s

l = int(input())
x=''
for i in range(l):
  x+=input()
#print(x)

x = re.sub('for (\d+)',r'(\1*(',x)
x = re.sub(r'add',r'1+',x)
x = re.sub(r'end',r'))+',x)
x = re.sub(r'\(\)',r'0',x)
x = re.sub(r'\*\)',r'*0)',x)
x = re.sub(r'\+\)',r')',x)
x = re.sub(r'\+$',r'',x)
#print(x)

s=[]
for i in x:
  #print(i)
  s.append(i)
  s = st(s)
ans = int(s[0])
print("OVERFLOW!!!") if ans>2**32-1 else print(ans)